1. Field of the Invention
The present invention is related to a water-proof structure of a Christmas lamp, especially to a water-proof pad which is formed integrally, thus the water-proof effect of positive polarity conducting piece is achieved.
2. Description of the Prior Art
In general, a serial of Christmas lamps includes lamp bases and lamps assembled on one ends of the lamp bases. If the lamps are used outdoors in order to prevent the rain to permeat into the lamp bases through the assembled interface between the lamps and the lamp base, thus American UL has defined a related standard.
In order to match said American UL standard, the China Patent Application 95228728.5 has disclosed a water-proof structure of a lamp base, in which a rubber water-proof ring is installed between the upper end of the lamp base and the lamp and a ring shape water-proof pad is installed between the lower end of the lamp base and contacting surface of an engaging plate. By the tightly enforcing of the rubber water-proof ring and the ring shape water-proof pad, the outside rain water will not flow into the lamp base.
However, in the structure of aforementioned patent application, the assembling interface of the water-proof ring between the inner rim of the upper end of the lamp base and the lamp need higher assembling precision. If the precision is insufficient or deformed, it is often that the lamp will not be assembled on a set position of said lamp base, i.e. the contact copper head on the lower end of the lamp will not contact with the positive polarity conducting piece.
Further, the shape of said water-proof pad is not the same as that the electric line radially passing through the lower end of the lamp base and the engaging plate, while the rain water will still has the probability to flow into the lamp base through the gap between the water-proof pad and the electric line. Thus in the patent application, a water-proof block is needed to further cover the conducting piece so to prevent the probable permeation.
From the structure of said patent application, in order to achieve the object of water-proof, three independent elements, a water-proof ring, a water-proof pad and a water-proof block, are included. Thus it has further increased the costs of fabrication and assembly.